Details

Autor(en) / Beteiligte

• Comolatti, Renzo
• Pigorini, Andrea
• Casarotto, Silvia
• Fecchio, Matteo
• Faria, Guilherme
• Sarasso, Simone
• Rosanova, Mario
• Gosseries, Olivia
• Boly, Mélanie
• Bodart, Olivier
• Ledoux, Didier
• Brichant, Jean-François
• Nobili, Lino
• Laureys, Steven
• Tononi, Giulio
• Massimini, Marcello
• Casali, Adenauer G.

Titel

A fast and general method to empirically estimate the complexity of brain responses to transcranial and intracranial stimulations

Ist Teil von

• Brain stimulation, 2019-09, Vol.12 (5), p.1280-1289

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2019

Quelle

MEDLINE

Beschreibungen/Notizen

• The Perturbational Complexity Index (PCI) was recently introduced to assess the capacity of thalamocortical circuits to engage in complex patterns of causal interactions. While showing high accuracy in detecting consciousness in brain-injured patients, PCI depends on elaborate experimental setups and offline processing, and has restricted applicability to other types of brain signals beyond transcranial magnetic stimulation and high-density EEG (TMS/hd-EEG) recordings. We aim to address these limitations by introducing PCIST, a fast method for estimating perturbational complexity of any given brain response signal. PCIST is based on dimensionality reduction and state transitions (ST) quantification of evoked potentials. The index was validated on a large dataset of TMS/hd-EEG recordings obtained from 108 healthy subjects and 108 brain-injured patients, and tested on sparse intracranial recordings (SEEG) of 9 patients undergoing intracranial single-pulse electrical stimulation (SPES) during wakefulness and sleep. When calculated on TMS/hd-EEG potentials, PCIST performed with the same accuracy as the original PCI, while improving on the previous method by being computed in less than a second and requiring a simpler set-up. In SPES/SEEG signals, the index was able to quantify a systematic reduction of intracranial complexity during sleep, confirming the occurrence of state-dependent changes in the effective connectivity of thalamocortical circuits, as originally assessed through TMS/hd-EEG. PCIST represents a fundamental advancement towards the implementation of a reliable and fast clinical tool for the bedside assessment of consciousness as well as a general measure to explore the neuronal mechanisms of loss/recovery of brain complexity across scales and models. •A general measure of spatiotemporal complexity of brain responses is proposed.•Consciousness can potentially be assessed online and using simpler EEG set-ups.•Perturbational complexity can be quantified at different brain scales.•Intracortical stimulations validate and extend TMS/EEG complexity measures.